From Portland drive 1 1/2 hours on I-84 to The Dalles, Oregon, then turn onto Hwy. 197 South towards Maupin, Oregon, in approx. 20 miles you will see the sign stating to turnoff to the left for the White River Falls State Park in approx. 4-5 miles on the right. Walk to the end of the parking lot and follow the trail down to where you look directly into the falls. Best times to photograph are first light as the sun shines directly into the canyon and onto the falls, and in late afternoon if you like backlighting.
Tygh Valley has gas and a country store. The park has restrooms, an onsite manager, and plenty of tables for those staying for the day. Summer brings crowds, Winters and early Spring the gate is closed, but you can enter by walking through the small opening for those on foot. The powerhouse, (not in use), sits below the falls, and their are swimming holes further down the river in about 1/4 - 1/2 mile. Stay clear of the banks when you see overhangs as there are strong currents where you may not be able to come out from underneath.
White River descends off of the White Glacier on the flanks of Mt. Hood before entering the Deschutes and then the Columbia River.